The general aim of this phase of the study of maturation and deviance is to continue investigation of the transition from adolescence to functional adulthood by examining further: (1) the extent to which pressures toward juvenile and young adult deviance originate in problems of adolescent stress; (2) the shifting commitments that occur in the competing areas of education, work, family, community conformity, and peer group involvement, as a part of the maturational reform process; (3) the effect upon maturation and deviance of wartime military service; and (4) the extent to which rural delinquency leads to adult maladjustment among those youth who migrate to the city and those who do not. This phase will place major emphasis on specifying and explaining (1) contemporary and subsequent life situations of crucial adolescent identities define during the primary phase of this study; and (2) the prior and contemporary life situations of critical young adult identities defined in terms of deviant, military, work, and educational experiences. Investigation also will center on examining the flows out of crucial adolescent identities, and flows into critical young adult identities. Cohorts of crucial adolescent and young adult identities have been defined as the identities became pertinent. The youth thus defined are traced prospectively and retroactively through yearly questionnaires given now to more than half of the original universe (all sophomore males in the high schools of a non-metropolitan Western county in 1964). The multiple-cohort design now comprises a 25 per cent simple random sample (N equals 309), and total populations of certain crucial adolescent and young adult identities: e.g., delinquents, drop-outs, and adult offenders. Two waves of data were collected prior to high school graduation and six subsequently; four additional are planned to extend coverage from mid-adolescence (age 15) to young adulthood (age 28). A large proportion of the central items are repeated in each time period. Supportive data include complete official records of academic performance, and juvenile and adult offenses.